The present invention relates to a dumbbell for weight lifting work and particularly to a dumbbell system with improved features that allows working and fortifying some specific muscles, including biceps, triceps and back muscles through a simultaneous and symmetrical work of both arms and alternatively one arm at a time.
Some of the existing muscle-working apparatii consist of complex and big exercise machines, and other kinds, like manual, small devices that are simply to use, like dumbbells.
Some of the existing manual dumbbells aim to work the chest and arms muscles are described in U.S. Pat. Nos. 4,813,669 and D242,865, incorporated herein by reference. Both patents show small dumbbells that are easy to manipulate, but that have a single weight amount, such that the user is prevented from changing or increasing the desirable weight.
This disadvantage is solved by U.S. Pat. Nos. 4,109,908 and 5,971,339, incorporated herein by reference, that allows changing the weight amount through small weight plates.
As seen in the U.S. Pat. No. 4,109,908, the device allows changing the weight, but the shape and functionality are complex because the device has to be supported over the forearm and the weight device rests over the forearm, causing a restricted working position. U.S. Pat. No. 5,971,339 shows a simpler shape, but prevents a symmetrical muscle workout or exercise since the device is not able to be lifted with both arms at a time.
The present invention allows changing the weight requested, allows working specific muscles work and a symmetrical workout with a dumbbell system comprising some suitable elements that can be combined to each other that improves the safety and provides a comfortable gripping feature.